Many foods contain their own defenses against viruses, fungi and bacteria. By consuming these foods, humans can also benefit from the plants' natural defenses. Foods that have been studied for their potency against a wide variety of pathogens include garlic, tea leaves, coconut and ginger.
Fresh GarlicFresh garlic. Photo Credit Stockbyte/Stockbyte/Getty Images
Garlic contains an active substance known as allicin, which is responsible for its anti-microbial activities. Allicin, which is released when fresh garlic is crushed, has shown to have anti-parasitic, anti-fungal and anti-bacterial activity. A 1999 study published in "Microbes and Infection" notes that garlic promotes anti-parasitic activity against intestinal parasites and anti-fungal activity against candida. Its anti-bacterial activity covers a wide range of multidrug-resistant strains of E. coli.
Tea LeavesGreen tea leaves. Photo Credit scorpp/iStock/Getty Images
Tea leaves display anti-microbial activity as a defense mechanism against insects and pathogens alike. Black tea and partly fermented oolong tea may be particularly effective against viruses, bacteria and fungi. A 2007 study published in "Molecular Nutrition & Food Research" notes that these teas contain two classes of phenolic compounds that may each possess anti-microbial properties. Another 2012 study published in "Recent Patents on Anti-ineffective Drug Discovery" notes that the anti-microbial effects of tea have been demonstrated against common and dangerous pathogens, including different strains of staphylococcus, E. coli and salmonella.
Coconut PartsCoconut and coconut meat. Photo Credit Taylor Hinton/iStock/Getty Images
Coconut, a plant with a variety of nutritional and medicinal uses, instigates anti-microbial activities against fungi, viruses and bacteria, as well as parasites. A 2011 paper published in the "Asian-Pacific Journal of Tropical Medicine" notes that the coconut kernel and coconut water possess these anti-pathogenic effects. The Coconut Research Center notes that coconuts have been used in traditional medicine to combat a variety of illnesses caused by bacteria and viruses. Some of these include bronchitis, the common flu, ulcers (commonly caused by the H. pylori bacteria), gonorrhea and skin infections.
A Super SpiceFresh ginger. Photo Credit Stockbyte/Stockbyte/Getty Images
Ginger, a spice that was used medically in ancient China, possesses a range of potent anti-microbial properties, as demonstrated by a variety of scientific studies. A 2013 study published in the "Journal of Ethnopharmacology" found that fresh ginger was effective against certain viruses in the human respiratory tract. A 2009 a study published in the "Global Journal of Pure and Applied Sciences" concluded that ginger possesses anti-bacterial properties against both of the common bacteria staphylococcus and streptococcus. A 2005 study published in "Biochemical and Biophysical Research Communications" found that ginger contains a protein that is also effective against a variety of fungi.